The quilt patch titled
Subject: vma: detect infinite loop in vma tree
has been removed from the -mm tree. Its filename was
vma-detect-infinite-loop-in-vma-tree.patch
This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx>
Subject: vma: detect infinite loop in vma tree
Date: Thu, 31 Oct 2024 15:36:08 -0400
There have been no reported infinite loops in the tree, but checking the
detection of an infinite loop during validation is simple enough. Add the
detection to the validate_mm() function so that error reports are clear
and don't just report stalls.
This does not protect against internal maple tree issues, but it does
detect too many vmas being returned from the tree.
The variance of +10 is to allow for the debugging output to be more useful
for nearly correct counts. In the event of more than 10 over the
map_count, the count will be set to -1 for easier identification of a
potential infinite loop.
Note that the mmap lock is held to ensure a consistent tree state during
the validation process.
[akpm@xxxxxxxxxxxxxxxxxxxx: add comment]
Link: https://lkml.kernel.org/r/20241031193608.1965366-1-Liam.Howlett@xxxxxxxxxx
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
Reviewed-by: Vlastimil Babka <vbabka@xxxxxxx>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>
Cc: Jann Horn <jannh@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vma.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
--- a/mm/vma.c~vma-detect-infinite-loop-in-vma-tree
+++ a/mm/vma.c
@@ -615,7 +615,11 @@ void validate_mm(struct mm_struct *mm)
anon_vma_unlock_read(anon_vma);
}
#endif
- i++;
+ /* Check for a infinite loop */
+ if (++i > mm->map_count + 10) {
+ i = -1;
+ break;
+ }
}
if (i != mm->map_count) {
pr_emerg("map_count %d vma iterator %d\n", mm->map_count, i);
_
Patches currently in -mm which might be from Liam.Howlett@xxxxxxxxxx are
